An Elementary Laboratory 
Study in Soils, 
Prepared by 
Prof. Joseph A.Jeffery 
of the M. A. C. 

s 

.04- 



For the Schools 
of Michigan 



Bulletin No. 27 
1908. 



Published by the 
State Superintendent 

of 
Public Instruction. 




Class. 
Book. 



^_51 



T.,. 



Copyright 1^". 



copyRiGirr DEPosrK 



AN 
ELEMENTARY LABORATORY STUDY 



IN 



S O I 1^ s 



SCHOOLS OF MICHIGAN 



JOSEPH A. jEFFERY, Professor of Agronomy. 
Michigan Agricultural College, Lansing. 



Published by the 
Superintendent of Public Instruction. 



LlbftARY Ot CONariESS" 
two Copies K9GVI»e;i 

l-EB 17 !908 



COPY 



? 



Copyright, 1907, 
BY JOSEPH A. JEFFERY. 



STATE OF MICHIGAN, 

1 ) K r ARTM ENT OF PUB fic INSTRUCT I OX. 

Lansing, Michigan, Jaimaiy 2, 1908. 

To ConuimHioncrs, Superintendents and Teachers: 

For a number of years educators have been advocating nature study as 
a part of the pubUc school curricuhmi, and at the present time there is a 
strong demand that agriculture be taught in the public schools. In order to 
assist superintendents and teachers in giving definite instruction along these 
lines. Professor Joseph A. Jeffery of the Michigan Agricultural College has 
prepared this pamphlet entitled An Elementary La]:)oratory Study in 
Soils. The material presented does not require an extended knowledge of 
chemistry and physics on the part of the teacher, and yet it deals with the 
vital points in this most important subject. The Agricultural College is' 
doing a great work for the State of Michigan, and we believe that the distri- 
!)ution and use of this pamphlet in our schools will give splendid opportunity 
for study on the part of our young people, and at the same time culti>'ate a 
■taste for agricultural pursuits. AVith this end in view the Department 
hereby expresses its appreciation of the services of Mr. Jeffery, and presents 
this pam])hlet to-the teachers of the State as a ground work for some definite 
instruction and study in the subject of soils. 

Very respectfully. 



A • / . Th^^~ 



Superintendent of Public Instruction 



tabi:e of (^ontenTvS. 



J'aKe. Hours. 

Introduction 7 

Equipment — laboratory 9 

Preliminary exercise 10 

Experiments 

I. Pore space in soil — artificial 11 2 

ir. Specific griivity of soil.'. 1'2 I 

in. Pore space in soil — natural 13 (> 

IV. Weight of soil — under artificial conditions 10 ."> 

v. Water-holding power of soils — artificial 17 2, 

VI. Water-holding power of soils — as affected by the 

presence of organic matter. 18 3 

VTI. Water-holding power of soils — as affected by the 

presence of clay 18 3 

VIII. Water in soils under natural conditions 19 3 

TX. Water in soil when plants cease to grow 20 -1 

X. Moisture in air-dry soil 22 2 

XT. Moisture losses from cultivated and uncultivated soil 

surfaces 22 8 

XTI. Effect of dry-earth mulches upon moisture losses.... 25 8 

XIII. The effect of water in the puddling or baking of soils. . 20 2 
Xn^. The effect of organic matter in soil upon the degree of 

puddling 20 2 

XV. The effect of sandy material in soil upon the degree of 

puddling 27 2 

XVI. A study of the variation in temperature of natural field 
or garden soils during the day at depths of 0, 3, 6, 

and 12 inches respectively 28 2 

XVII. A study of the variation in temperature of natural 
field or garden soils during the day at lesser depths 

than in Experiment XVI 29 3 

XVIII. The effect of slope upon the temperature of the soil . . 29 3 
XIX. The effect of color upon the temperature of soil (with 

air-dry soils in laboratory) 30 5 



G (X)NTENrS. 

I'a^'c. IJoui's. 

XX. The effeft, of color upcMi the leniperaturo of soils (with 

moist soil and field conditions) 32 (» 

XXL The effect of moisture upon the temperature of the soil 33 2 
XXII. The effect of tilth upon the temperatui-e of +he soil 34 2 
XXIII. The effect of smoothness of surface ut)on soil tempera- 
ture '^^ - 



INTRODUCTION. 



The object of this course is to give to the pupil an opportunity to demon- 
strate for himself a few of the more important facts concerning soils and soil 
management. It is believed that when he has done this, his reading upon 
these things will be much more intelligently done and thfir application to 
farm practice will be more fully appreciated. 

The teacher may find it desirable to change the order of the experiments; 
he may desire to change the plan of some of them. The discussions following 
some of the experiments may suggest other experiments, and it willcloubtless 
add much to the interest of the work to allow pupils, from time to time, to 
develop and perform an original experiment so suggested. It will often be 
necessary to assist the pupil to a ])roper interpretation of liis results in such 
an experiment. 

The results of every experiment should be discussed — 

First, As to their bearing upon farm practice so far as the ]jupils are ac- 
quainted with it, and 

Second, As to how far they illustrate or confirm anything Ihey may have 
read in the text books or elsewhere, or may have observed in practice. 



LABORATORY EQUIPMENT. 

It is desirable, of course, to have a regularly equipped laboratory. It 
need not necessarily be a large room or expensively equipped. There should 
be some tables to work on. There should be a drying oven, one good 
balance weighing to one-tenth gram, a kitchen scale or its equivalent, ranging 
from one ounce to at least twenty-four pounds. If the building is not sup- 
plied with gas, there should be a gasoline stove and an alcohol lamp. 

In addition to the above, the following apparatus and^material will be 
needed: 

2 doz, deep gallon jars. 

5 doz. one-quart pudding or bean pans. 
2 doz. two-quart pudding or bean pans. 

2 doz. 8-inch pie tins (with nearly square shoulders if they can be se- 
cured). 

1 doz. coffee cups. 

10 feet No. 12 galvanized wire. 

1 garden rake. 

1 garden hoe. 

1 garden spade. 

2 4-inch x 4-inch x 4-inch boxes of wood or metal without covers (see 
Fig. 3.) 

1 soil sieve about 18 inches x 30 inches and 4 inches deep, with screen 
having 6 meshes to the inch (see Fig. 2). 

1 fine meal sieve. 

2 soil tubes (say 1^ inch b}^ 3^ inches). 

1 funnel rack, to carry 8 fimnels (see Fig. 9). 

6 small soil scoops of bone, tin or wood. 

J iron rod, |-inch by 18 inches long, rounded at end. 

3 granite ware quart cups. 

6 small rods of wood, ^-inch by 12 inches long. 
1 straight edge 16 inches long. 
1 gauge (see Fig. 10a). 

12 accurately graduated glass thermometers with lower end of stem as 
long as possible. 

3 soil thermometers — one 3-inch, one 6-inch, and one 12-inch. (These 
are desirable but can be dispensed with.) 

1 doz. 4-inch glass funnels. 

4 doz. 4-oz. beakers (125 c. c), or small glass tumblers. 

1 doz. 600 c. c. Hpped beakers. 
3 100 c. c. graduates. 

2 200 c. c. graduates. 

1 doz. l|-inch thistle tubes (see Fig. 2). 

3 pounds |-inch glass tubing. 

6 glass rods 3-16 inch by 8 inches long ("stirring rods"). 



10 



DEPARTMENT OF TUBLIC lNSTRU(rjTON. 



1 doz. No. 14 corks. 

6 doz. 4-oz. screw cap jars. 

6 doz. |-inch by 5-inch screw caj) liomeos. 

5 pounds paraffin. 

] set of tools— -liainmer^ saw. pliers, nippers, scissors etc. 

There should be kept in stock two or three bushel lots of at least four 
kinds of soil — clay, loam, sandy soil, and muck soil, and also coarse sand 
and fine sand, all of which .should V.ie air dried and carefully screened. In 
screeniuij these soils a fine meal sieve may be used. 



PRELIMINARY EXERCISE. 

1. Have each pupil bring in quart samples of as many distinct kinds of 
soil as can be found. Samples should be obtained by digging a hole having 
perpendiculai" walls, to the depth of the plowed soil, or in virgin soil to the 
depth of the soil jjroper as indicated by the darker color due to the presence 
of a larger amount of organic matter in the soil. In muck >-oi!s take samples 
to the depth of six inches. Mix thoroughly the sample soil taken from the 
hole before taking the c[uart sample. 

2. Each Cjuart sample should be thoroughly air dried, after which all 
samples should be examined and grouped on the basis of color, the propor- 
tions of coarse and fine material making u]) the sample, and the general 
mellowness of the sample. 

There should "be at least four general groups fountl in most localities— cla}', 
loam, sandy soil and muck. If all of these cannot be found in a locality, 
those lacking should be secured from other localities. 

3. Charactei'istic samples of these groups of soils should be preserved in 
screw capped homeos. or in 4-oz. screw cap jars as may be prefefred (see 
d and e. Fig. 3). Thes(^ samples should be saved for futin-e reference anrl 
comparison. 

4. It would be interesting to have pupils bring in quart samples of the first 
six inches of the sub-soil corresponding to the soils they bring. These sub- 
soils should be examined and grouped in the same manner as the soils. 



^gSgQg^ 




Fig. 1. a ami b, iwu styles of torsion balance with afconipaiiyiiig 
form of kitchen balance weighing to 24 potiniis by ounces. 



weiglit^ 



;i roimiioii 



STUDY IN SOILS. 



11 




Fig. 2. Here are shown from left to'righta cake of'paraffin, funnel, filter 
paper, graduate rylinrler, beaker, thistle-tube funnel, box of labels^and soil 
sieve. 




Fig. 3. a, quart bean pan; 6, pie tin for cover; c, wooden soil box; d, 4-oz. screw- 
cap jar; e, screw-cap homeo; /, soil scoop; g, brass soil tube. 



Experiment I. 



Pore Space in Soil. — Artificial. 



Apparatus needed: 

1 deep metallic vessel ranging in capacity from J pint to 1 })int. It may 
be made by melting off the open end of a can in which canned corn or 
peas are purchased^ or it may be made by soldering a piece of sheet brass 
overdone end of a piece of brass pipe 1^- inches in diameter and 4 inches 
long (see g Fig. .3). Call these soil tubes. 

1 round tamper of wood or one of cork having a glass or wood handle. 

1 small piece of wood 12 inches long and ^-iiich S(|iiare. 

1 vessel of one })int capacity. 

1 balance or scale. 

1 sample each of sandy, loamy, and muck soil. 
3 



12 DEPARTMENT OF PUBLIC INSTRUCTION. 

Before beginning the experiment opinions may be called for as to how 
compact a mass of soil may be, as to how much unoccupied space may 
occur between the particles of soil in the mass with reasons for believing 
there is or is not any such unoccupied space. 

The experiment: 

1. Weigh an empty soil tube and record its weight. 

2. Fill this soil tube with water till even with the top; weigh and record 
weight. 

3. Empty and thoroughly dry this soil tube. 

4. Now fill with one of the soils — say the sandy soil. To do this fill the 
tube heaping full, hold it fi.rmly upon some solid surface and tap the 
sides lightly with the small piece of wood mentioned in the list of ap- 
paratus. The tapping will cause the soil to settle. See to it that all 
the while the packing is going on the surface of the soil is kept well 
rounded by adding more soil. Vary the force of the tapping and 
do not do all the tapping at one point. 

5. When settling of soil ceases, with the straight edge strike off the soil 
even with the upper edge of the soil tube. 

6. Weigh the tube with soil content and record weight. 

7. Slowly add water to the soil in the tube until the water ceases to be 
taken and stands as even with the surface of the soil tube as when the 
tube was previously filled with water. 

Caution: During the adding of the water the sides of the tube shoidd he tapped 
to loosen the air huhhles which might cling to the soil walls and so keep out 
the water. 

8. Weigh and record weight. 

9. Compute what part of the capacity of the soil tube is filled by soil and 
what part by water. 

What previously occupied the space in the tube now occupied by water? 
In performing the experiment use an outline similar to the following: 

1. Weight of soil tube full of water 

2. Weight of empty soil tube 



3. Weight of water content of tube 

4. Weight of tube full of soil 

5. Weight of tube, soil and water 

6. Weight of water added to soil 

7. Per cent of space in tube unoccupied by soil 

10. Repeat this experiment, using a loam and a muck soil. 
Is it desirable that there be pore space in soil? Why? 

EXPEKIMENT II. 

Specific Gravity of Soil. 

It is often desired to know the weight of a volume of soil (not including 
pore space) as compared with a like volume of water. This relative 
weight is known as specific gravity. 

Using the necessary weights from the table you filled out in Experiment I 
fill out the following table: 



STUDY IN SOILS. - 13 

1. Weight of water required to fill soil tube (3) 

2. Weight of water added to fill space iu soil (H) 

3. Difference 

4. Weight of tube and soil content 

5. Weight of empty soil tube 

6. Weight of soil in tube 

7. Select from these figures the weiglit of the volume of water eiiual to the volume 
of the soil used in the tube. 

8. Determine and indicate the relative weight of the soil as' compai'ed with that 
of the equal volume of water, which is the^ 

Specific gravity of the soil 

9. Determine the specific gravity of at least two different soils. 

Experiment III. 

Pore Space in Soil.— Natural. 

Apparatus and matcruil needed: . 
A spatula or old sharp case knife. 
2 pieces of window glass 8 inches x 10 inches. 
1 pound paraffin. 

1 quart pan in which to melt the paraffin. 
1 two-quart pan. 
1 250 c. c. beaker. 

A strip of card board 3| inches b_y 11 inches. 
A piece of the same card board 3| inches square. 

The experiment: 

1. From some convenient field or garden area cut a cube of soil of approx- 
imately 4-inch face. Lay on a board or other smooth surface and con- 
vey to laboratory. 

2. Place this cube upon one of its faces and with the spatula or knife true 
one of the perpendicular faces ; then cut away and true the opposite face 
so that the thickness of the soil between these trued faces shall be al^out 
three inches. (It is suggested that the face first trued be the ujiper 
face as it was taken from the field.) 

3. Turn the block of soil upon one of the ])ieces of glass with the surface 
first trued down. 

4. Now cut down and true the remaining four faces so that each dimension 
shall be about 3 inches. See Fig. 4. 

5. Slightly round all the edges excepting those resting against the glass. 
G. Crease the cardboard strip at distances of 3^- inches as shown in Fig. 4. 

Then bend and fasten the ends with a strip of paper and mucilage. 

7. Place the case of paper over the cube of soil as shown in Fig. 5, so that 
the walls of the case shall be about i-inch in all places from the walls of 
the cube of soil. Pack some loose soil about the lower outside edges of 
the paper case. See Fig. 5. 

8. Melt about one pound of the paraffin and allow it to cool until its tem- 
perature is just above the melting point. 

0. Slowly pour the melted paraffin into the pa[ier case about the soil until 
the paraffin stands even with the top of the paper case. 

10. Place the remaining piece of cardboard upon the surface of the melted 
paraffin in paper case and allow paraffin to coo!. See Fig. 6. 



14 



DEPARTMENT OF PUBLIC INSTHUCTIUN. 




Fig. 4. Cube of soil ready to be encased, and the 
with .spalula, werdcr and loose .soil. 



d lioard \o be used foi- the outer case, 




Fig. 5. Thejouter paper case in place ready for the paraffin, 
for outer case, tin cup, bunsen burner, and glass stirring rod. 



Paper bottom 



11. After a few hours loosen the paraffin case from the glass. (This can 
usuallv be done b}' turning the case over so that the glass will be up, and 
tappiiig the glass lightly. Otherwise pour a little hot water upon the 
glass.) See Fig. 7. 

12? With a one-eighth inch glass or wooden rod make a hole 2^i inches 
deep near the center of the soil. 

13. Pour water very slowly into this hole until the openings in the soil are 
tlioroughly filled and the v/ater stands even with the top of the soil. 

14. With a "glass rod or other dull tool remove to the two-quart pan as 
much of the content of the paper par.nffin case as you can without mar- 
riuii' the inner s\u"face of the case. 



STUDY IN SOILS. 



15 




Fig. 6. Tlie encasing of the soil is here completed. 




Fig. 7. The enca.seil cube of soil loosened from the glass 
and placed right side up ui)on the glass plate. 

15. Measure into a beaker 200 grams (c. c.) of water, aii'l with this wash 
the remaining soil in the paper-]:)araffin case into the two-quart pan. Use 
aU of the 200 grams of water. 

16. Weigh the two-quart pan ayid contents and record the weight. 

17. Place the two-quart pan in a drying oven having a temperature of 
212° to 225° F. (100° to 110° C.) until it ceases to'lose weight. 

18. Weigh the pan Avith dry content and record weight. 
"19. Weigh the paper-paraffin case, empt3\ and record weight. 

20. Fill the case even full of water, weigh and record weight. 
Use a table something like the following; 



16 DEPARTMENT OF PUBLIC INSTRUCTION. 

Weight of paper- paraffin case full of water 

Weight of paper-paraffin case, empty 

Weight of water case holds 

Weight of pan, soil and water 

Weight of pan and soil after drying 

Weight of water lost in drying 

Weight of water used in washing 

Weight of water in saturated soil in case 

Using the weight of v.ater which the paper-paraffin case holds and tlio 
waiter contained in the saturated soil in the case, estimate the amount 
of pore space in the soil in the case. 

ISXPEKIMENT lY . 

Weight of Soils under Artificial Conditions. 

Apparatus and material needed: 
A box of wood or metal 4 inches in each dimension, open on one side. 

Call it a soil box. (Fig. 3.) 
A small mallet or a piece of wood 12 inches long and ^-inch sqr.are. 
.A. straight edge of some sort. 
3 pints each of say, four soils — a sand}'' soil, a loam soil, a clay soil, and a 

muck soil, all air-dry. 

The experiment: 
-1. Weigh soil box and record weight. 

2. Fill the soil box heaping full Vvith the sandy soil and settle as completely 
as possible by tapping the sides of the soil box with the mallet or stick. 

Caution: Hold the box firmly upon some solifl surface while tapping and see 
to it that soil is added from time to time to keep the surface of soil in the box 
■well rounded all the lohile. Vary the force of the tapping. 

3. When the soil ceases to settle strike off the surface of soil even ^^ ith lop 
of box. 

4. Weigh the box with its contents and i-ecord weight. 

5. Determine the weight of soil in box. 

6. Estimate the weight of a cubic foot of sucli soil. 
Use a form like the following: 

1. Weight of soil box and soil content 

2. Weight of soil box 

3. Weight of soil in box r 

4. Estimated weight of a cubic foot of this soil 

Alternate. 

The above experiment may be performed by using a tin pea or corn can 
with the open end melted off. 

In using such a can its capacity should be determined as follows: 

1. Weigh the can empty and record weight. 

2. Fill the can with water. 

3. Weigh the can full of water and record weight. 

4. Subtracthig the weight of the empty can from the weight of the can 



STUDY IN SOILS. 17 

filled with water gives the weight of the volume of water which the can holds. 
One cu. inch of v/ater weighs .036 lbs. or 16.33 grams. 
5. Having the weight of the water which the can holds, estimate its capacity. 
Use a form hke the following: 

1. Weight of can full of water 

2. Weight of can, empty / 

Weight of water in can 

3. Estimated volume of water in can in cubic inches 

From this point proceed as in soil-box experiment. 

Can you plan and execute an experiment by whick you can determine the 
weiyhi per cubic foot of field soils — soil under natural conditioyis? 

Experiment V. 

Water-holding Power of Soils. — Artificial. 

Apparatus and materials needed: 

8 four-inch glass funnels. 

1 package of 6-inch filter papers. 

1 rack for carrying the eight funnels. (This rack may be made of a board 
1 inch X 6 inches — 5 feet long, with eight three-inch holes bored at 
distances of 7 inches apart center to center. The holes may be bored 
with an extension bit. When in use let this rack rest on supports six 
to eight inches high.) See Fig. 8. 

8 four-ounce beakers or ordinary glass tumblers. 

1 100 c. c. graduate cylinder. 

4 lots of air-dry soil — a sandy soil, a loamy soil, a clay soil and a muck soil. 




Fig. s. i-unnels in place in simple wooden rack with beakers under tlie uinnels 
in experiment to study water-holding power of soils. 

The experiment: 

1. Mount the eight funnels in the rack. 

2. Fold a filter paper for each funnel, set in place and wet so that it will 
stay in place. 

3. Weigh out and introduce into each of two funnels 100 grams of the 
sandy soil. 

4. Weigh out and introduce into each of two other funnels 100 grams of 
the clay soil . 

5. Weigh out and introduce into each of two other funnels 100 grams of 
loamy soil. 

6. Weigh out and introduce into each of the two remaining funnels 50 
grams of the muck, soil. 

7. Place a beaker under each funnel. 



18 



DEPARTMENT OF PUBLIC INSTRUCTION. 



8. Measure 100 c. c. of water into each of the funnels- containing the sand\, 
clay, and loamy soils. 

9. Measure 150 c. c. of water into each of the funnels containing the muck 
soils. 

10. When the water has ceased to drain into the beakers from all the soils 
measure and record the amount of water that has drained from each 
soil. 

What does a c. c. of water weigh? 

Introduce data into a table like tlie following: 

Water-holding Capacity of Soiis. 



No. 


Kind 

of 

■soil. 


Weight 

of 

soil. 


Water 
added. 


Water 
recovered . 


Water 
retained 
by soil. 


Average 
amount 
of water 
retained 
by soil. 


% of 

water 

retained. 


1 
















2 


Sandy . . 










J 




















3 


Clav .... 














4 . . . . 


Clav 






























,5 


Ijoani 














G 


































Muck . . 














8 


Muck 































1 1 . Remember that in computing the per cent of water retained by the soil, 

the weight of dry soil is used as the base. 

12. Account for th.e differen.'^es in the amounts of water retained by the 
sauil and the clay; tlie sand and the muck; the sand and the loam. 

EXPEUIMENT Vr. 

Water-holding Power of Soils as Affected by Presence of Organic Matter. 

1. Repeat Experiment V, using mix tiu"es of sand and muck as follows: 
(]) All sand and no muck, (2);80% sand and 20^;^, muck, (3) 60% sand 
and 40% muck, and (4) 40% sand and 60%, muck. 

2. Account for the differences in the percentage amoimts of water retained 
by the different comlnnations of sand and muck. 

3. Do the percentage amounts of water retained by the different condo- 
nations bear any relation to the amoimts of muck or sand in the combi- 
nations? 



KXPKRIMENT VII. 

Water-holding Power of Soils as Affected by Amount of Clay Present. 

1. Repeat Experiment V, usina: combinations of sand and clav as follows: 
0) 100% of sand, (2) 80% of sand and 20% of clav, (3) 60%, of sand 
and 40%: of clay, and (4) 40% of sand and 60% clay. 



Study in soils. 



19 



2. Account for the differences in the percentage amounts of water retained 
by the different combinations. 

3. Do the percentage amounts of water retained by the different combina- 
tions of sand and clay bear any relation to the amounts of clay or sand 
in the combinations? 

Experiment VTTT. 

Water in Soils under Natural Conditions. 

Apparatus needed: 
A sharp spade. 

.3 one-quart bean or pudding pans. 

3 eight-inch pie tins to be used as covers for the pans. 
The p<ans and pie tins should be permanently numbered. 




Fig. 9. Galvanized iron drying oven in 
place upon an ordinary two-burner gasoline 
stove. This oven is 17 inches wide x 13 
inches deep x 48 inches high. 



The experiment: 

1. At a point in a field or garden where the moisture conditions seem good 
for growing a crop, dig with, the s])ade to the depth of the soil— five inches 
to eight inches. On one side of the hole have the wall perpendic lar, 
and remove all loose soil from the bottom of the hole. 



20. 



DEPARTMENT OF PUBLIC INSTRUC'JlON. 



2. With the spade cut off, from, top to bottom, about one inch of the face 
of the perpendicular wall, allowing the soil to fall to the bottom of the 
hole. 

3. As quickly as possible^ thoroughly mix the soil so cut from the wall; 
fill one of the pans two-thirds full with the mixed soil and cover with a 
pie tin. 

4. Move off a phort distance, dig another hole and take another sample 
in the same manner, placing the sample in another pan. 

5. Move to a third place and take a third sample, placing it in another 
pan. 

6. On arriving at the laboratorj^ weigh each pan with its contents, record- 
ing the number and weight in each case. 

7. The pans with their contents should now be subjected to a tempera- 
ture of 212° to 225°F. until the pans cease to lose weight. This will re- 
quire from S hours to 16 hours, depending upon the soil. See Fig. 9. 

8. When dr}'-, weigh each pan with its contents and record. 

9. Remove the dry soil from each pan, weigh the pan and record. 

10. Determine the per cent of moisture in each soil. 
Use a form like the following: 

Natural Water Content of Soils. 



Sample 

of 

soil. 


No. 

of 

pan. 


Weight 

of 

pan. 


Weight 
of pan 
and wet 
content. 


Weight 
of pan 
and dry 
content. 


Moisture 
lost. 


Weight 

of 

dry 

soil. 


% of 
moisture. 


1 
















2 








3 


, 








1 







The per cent of moisture in soil is found by dividing the weight of moisture 
lost b}'' the weight of dry soil. 

EXPFKIMF.NT IX. 



Water in Soil When Plants Cease to Grow. 
A— Under Natural Conditions. 

ApparatiLs needed: 

Same as those required in Experiment VIII. 

The experiment: 

1. Where it is possible, select an area where plants are suffering from 
drought, that is, where a drought has continued till field plants have 
begun to turn yellow or to wilt badly, and determiine the moisture 
content of the soil, proceeding in everv particular as in experiment 
VIIT. 

Use a table like that in Experiment VIII. 



STUDY IN SOILS. 



21 



Altbrnate. B— Under Artificial Conditions. 

Where field oonditions are not found as above, the work may be done under 
artificial conditions. 

Apparatus needed: 

1 deep gallon jar. 

2 one-quart pans with pie tins for covers. 
A few kernels of good seed corn or oats. 

A gallon of field soil in good tilth and moisture condition. 

The experiment: 

i. Fill the jar to within a half-inch of the top with the soil, packing liohtly. 
Be sure that the soil is in about the right condition of moisture for"]>low- 
ing or for being planted to seed. 

2. At the time of filling the jar, take two samples of the soils in pans and 
determine the moisture^ contained. 

3. Weigh the jar and soil content and record weight. 

4. Plant six kernels of oats or three kernels of corn three-fourths inch 
deep in the soil in the jar. After they have germinated, thin to four 
plants of oats or two plants of corn. 

5. Until the oats are eight inches high or the corn plants are twelve inches 
high, weigh the jar once each week and add water enough to bring the 
weight up to the original weight, recording the same in each caser 

G. When the crop has reached the height indicated above, allow the jar 

to stand until the plants show decided effects of lack of moisture. 
7. Weigh jar and contents and record weight. 
S. Remove the crop, then remove the soil from the jar. thoroughly mix, 

and sift a portion through a ooarse sieve to remove roots. 
9. Take two siimples of this sifted soil and determine moisture content 

as in Experiment VIII. ' 

The preparation of the soil and the taking of samples should be done 

without undue loss of time. 
Use a table something like this: 



Water in Soil When Plants Cease to Grow. 





1st week. 


2d week 


3d week 


4th week 


5th week 


Moisture content at start and 
close of experiment. 


jar and 
moist soil. 


■S'.S. 


^1 




e3T3 














d 


^ 3 

MM 

^•3 


c 
"o-o-S 




i 

1 


































































it 

5 (2 















































It would be worth while to use two soils for experiment B— a rather heavy 
soil and a light soil. 



22 



DEPARTMENT OF PUBLIC IxNfSTRUCTlON. 



Experiment X. 

Moisture in Air-dry Soil. 

Apparatus and materials needed: 

4 two-quart pans. 

4 soils — a sandy soil, a loamy soil, a clay soil, and a niuclc soil — all air- 
dry. It would be well to let all these lots of soil stand together in an. 
open room for a few days before using in this experiment. 

If all these soils are not available use as many as can l)e secured. 

The experiment: 

1. Carefully numl^er and weigh 4 pans and record their weights. 

2. Into three pans weigh 1000 grams of sandy soil, of loamy soil, and cla}' 
soil respectively, and into the fourth pan weigh 500 grams of tlie 
muck soil. 

3. Subject the pans and contents to a temperature of 212° to 225° F., or 
100° to 110° C. until they cease to lose weight. 

4. Weigli pans and di'y contents and record weights. 
Use a table like the following: 

Moisture in Air-dry Soils. 



Kind 

of 

soil. 


No. 

of 

pan. 


Weight 

of 

pan. 


Weight 
of pan 

and 
air-dry 

soil. 


Weight 

of pan 

and 

dry 

soil. 


Moisture 
lost. 


Weight 
of dry 

soil. 


%of 
moisture. 


Order 

of 

moisture. 










1 


































1 








1 i 1- 







Offer any good reasons that may orcui- to you for any differences that may 
have been found. 



Experiment XI. 

Moisture Losses from Cultivated and Uncultivated Soil Surfaces. 

(Read directions for Experiment XII liefore performing tliis one.) 

Apparatus and materials needed: 
6 deep one gallon jars. 
1 straight edge. 
1 lipped beaker. 
A gauge (see Fig. 10). 
A four-c{uart pan. 
A small scoop. 
A quart cup. 



STUDY IN S01J.8. 



23 




Fig. 10. n, gauge for removing soil from jars 
in cultivation e.xperiment. h, common garden 
weeiier. c, simple wooden tamper that may bc 
used in compacting .soil in boxes or jars. 

G pieces three-eighths inch glass tubing or 6 ghiss thistle tube funnels. 

(The glass tubes or the funnel stems should 1)e one inch longer 

than the height of the jars.) 
U bushels of good field soil, prefera])ly a sandy loam. (This soil should 

be screened to remove large i)ebbles and coarse materials, and should 

be in good moisture condition for plowing or cropping.) 
1 gallon of very coarse sand. 

Experiment : 

1 . Thoroughly mix the one and a half bushels of soil. Be sure the condition 
of moisture is right. If too dry add water during the mixing. Shovel 
into a compact heap. 

2. Number the six jars 1 to 6 and place them in order near the heap of 
soil. 

3. Place in the bottom of each jar one pint of the coarse sand, spreading 
evenly over the bottom. 

4. Place a piece of the glass tubing or a funnel in each jar, against the 
side of the jar, and with the lower end resting on the sand. • A piece of 
light wire properly bent over the edge of the jar will hold the tubing or 
funnel in place during the filling. 

5. Add a struck-off cup of soil to jar ninnbei- 1, tlien one to number 2, 
and so on till each jar has received one c^uart of soil. Spread out the 
soil in each jar and pack firmly with the hand or with the bottom of the 
cup, being careful to treat the soil in the six jars, uniformly. 



24 



DEPARTMENT OV PUBLIC INSTRUCTION. 



6. Repeat the addition and packing of soil described in 5 nntil each jar is 
rounding full. 

7. When the jars have been thus filled, strike off each surface even with 
the rim of the jar, using a straight-edge. 

8. Set jars number 1 and number" 6 to one side. 

9. Set the gauge so that the blade shall extend one inch below the edge 
of wood frame and with gauge and scoop remove the soil from the sur- 
face of number 2 and number 5 to the depth of one inch, placing the 
soil in the pan. Thoroughly crumble wjth the hands the soil thus re- 
moved and return to the jars. This will fill the jars rounding full 
again. Tap lightly. Then with straight-edge strike off each surface 
even with rim of jar. Carefully set jars 2 and 5 aside. 

10. Set the gauge so that the blade shall extend two inches below edge of 
wooden frame, and with gauge and scoop remove the soil from surface 
of jars number 3 and number 4 to the depth of two inches, placing the 
soil in the pan. Thoroughly mix and return to jars, tap jars and strike 
off as in 9. 

Note — Observe that we have secured in jars 2. 5, 3 and 4 what we secure in the field by cultivat- 
ing one inch and two inches deep respectively. In the jars, however, we have secured much greater 
uniformity of both depth and stirring of soil. 

11. Add i pound of water to each jar through the tube or funnel. 

12. Weigh and record weight of each jar in order. (See Fig. 11.) 




Fig. 11. Showing jars as they appear when filled in Experiment XI. One of the 
jars rests upon platform of the kitchen balance. 

13. Place the six jars in order in some place sufficiently sheltered to pro- 
tect from rains and birds. 

14. At the end of one week weigh each jar, record weight and add water 
through the tube or funnel sufficient to bring the jar and contents up 
to the original weight. 

Note — To bring up to weight leave the jur on scale and add water lliiuugli tube or funnel very 
slowly. 

15. Repeat 14 at the end of the 2nd, 3rd, 4th, and 5th weeks. 

16. Determine the total loss by evaporation from each jar. 



STUDY IN SOILS. 



25 



17. Compare the individual losses. 

18. Average the losses of duplicates — 1 and 6, 2 and 5, and 3 and 4, and 
compare the averages. 

19. Using the averages obtained in 18, determine the losses per day per 
acre, with no cultivation, one inch of cultivation, and two inches of cul- 
tivation. 

Table of Moisture Losses from Cultivated Soils. 





c 




End of 
1st week 


End of 
2d week 


End of 
3d week 


End of 
4th week 


End of 
5th week 


— ."O 




1 

si 


Loss per acre 
per day. 


8-2. 
p. 


-J 








i 


OS'S 


1 




1 


tl-a 


Poiinds. 


Tons. 































































































































































































































































20. Account for differences in average losses. 
What does the experiment teach? 

Experiment XII. , • • 

Effect of Dry-earth Mulches upon Moisture Losses. 

Apparatus and materials needed: 

6 deep one-gallon jars. 

1 straight-edge. 
, 1 gauge. 

1 small scoop. 

1 lipped beaker or cylinder (8 oz. or 250 c. c.) 

1 four-quart pan. 

1 quart cup. 

6 pieces |-inch tubing of 6 thistle-tube funnels as described in Experi- 
ment XI. 

H bushels of good field soil, preferably a sandy loam, as described in Ex- 
periment XL 

1 gallon of the same soil thoroughly air-dryed. 

1 gallon very coarse sand. 

The experiment: 

1. Fill the six jars with soil, carefully following directions 1 to 8 in Ex- 
periment XI. 

2. With scoop and gauge carefully remove the surface soil from jars 2 
and 5 to the depth of one inch. Do not return soil. 

3. With scoop and gauge carefully remove the surface soil from jars 3 
and 4 to the depth of two inches. Do not return soil. 

4. Introduce into jars 2, 5, 3, and 4 to rounding full the air-dry soil, tap 
lightly, and with straight-edge strike off surfaces even with rim of jars. 



20 DEPARTMENT OF PXiBLIC IN8TRUCTI0N. 

5. Add eight ounces of water to each of the six jars through tube or funnel. 

6. Weigh each jar and record weight. 

7. At the end of each week, for five weeks, weigh each jar, record weight, 
and add slowly sufficient water to Ijring weight \\\) to the original weight 
as in Experhnent XI. 

8. Determine the total loss for each pan. 

9. Compare losses. 

10. Average the losses of the duplicate jars, 1 and 6, 2 and 5. and '.i and 4, 
and compare. 

11. Estimate the losses per day per acre, using averages only. 
Use a table similar to that in Experiment XL 

Suggest any practical application of the knowledge gained from this ex- 
periment. 

It would be well to perform this experiment in connection with Exjieriment 
Xr, in which case jars 1 and 6 of this experiment could be omitted. With 
slight changes, too, one table could be made to hold all data. 

EXPERIMKNT XIIT. 

The Effect of Water in the Puddling or Baking of Soils. 

Apparalus and materiuh needed: 

4 coffee cups, or 4 3-inch evaporating dishes. 

4 one-pint lots of the following soils, well moistened — a sandy soil, a 
loam, a clay soil, and a muck soil. 

The experiment: 

1. Weigh out 30 grams each of the sandy soil, the loam and the clay soil 
and 15 grams of the muck soil, placing each weighed lot in a separate 
cup or dish. 

2. Introduce into each cup or dish sufficient water to slightly more tliaii 
completely cover the soil in it. 

3. Place the cup or dishes with their contents in a warm dry place and 
allow to stand until all the water has evaporated and the remaining 
soil appears to be thoroughly dr}-. 

4. After this drying is complete examine these soils and note any tliffer- 
ences in the compactness of the masses. 

5. Account for these differences. 

Perhaps you may be able to measure in a cpiantitative way the firmness 
of these dry masses of soil. 

Have you ever observed as complete compacting of the surface soil in a 
corn field? 

Can you explain how a young corn plant may reach the surface of a soil 
in such condition? 

Suggest some means of preventing the .puddling of soils. 

Experiment XIV. 
Effect of Organic Matter in Soil upon the Degree of Puddling or Baking. 

Apparatus and material needed: 

5 coffee cups or 5 3-inch evaporating dishes. 

2 one-quart lots of air-dry soil, one of clay and one of nnick. 
1 600 c. c. beaker or graduate. 



S'J'UDY IN SOIL8. 27 

The experiment: 

1. Into the five cups or the five dishes introduce soil as follows: 

1st — 24 grams of clay. 

2nd — 18 grams of clay and 6 grams of muck. 
3rd— 12 grams of clay and 12 grains of muck. 
4th — 6 grams of clay and IS grams of muck. 
5th — 24 grams of muck. 
What are the percentage amounts in each case? 

2. Mix the contents of cups or dishes 2, 3, and 4 thoroughly. 

3. Add slowly to each cup or dish sufficient water to cover the soil one- 
fourth inch. 

4. Place cups or dishes and contents in a warm dry place, and allow to 
stand until thoroughly dry. 

5. Note differences in compactness of the dried masses of soil, and so far 
as you can, account for the differences. 

6. If you can, measure the differences. 

7. Do the results of this experiment suggest any method of farm practice? 

Experiment XV. 

Effect of Sandy Material in Soil upon the Degree of Puddling. 

Apparatus and materials needed: 

Same as in last experiment exce[)t that ([uart lots of air-dry clay and sand 
are to be used. 

The experiment: 

]. Into the five cups or the five dishes introduce soil as follows: 

1st —24 grams of clay. 

2nd — 18 grams of clay and 6 grams of sand. 

3rd — 12 grams of clay and 12 grams of sand. 

4th — 6 grams of clay and 18 grams of sand. 

5th — 24 grams of sand. 
From this point proceed as in experiment XIV. 



8011; TF^MPER.4TURE. 

For this work it is desirable, though not absolutely necessary, to have a 
set of all-glass soil thermometers, one three-inch, one six-inch, and one 
twelve-inch. (These can be purchased of Henry Green Sc Co., Brooklyn, 
N. Y.) Whether this set can be afforded or not, there should be provided 
one dozen accurately graduated all-glass thermometers. For this work 
Fahrenheit thermometers will probably prove best, and they should be suffi- 
ciently long in the lower stem, if possible, to give a length of three inches 
between the middle of the bulb and the 40° mark. 

With such a set of soil thermometers as that indicated above, the tem- 
perature of the soil may be observed at depths of 3 inches, 6 inches and 12 
inches respectively. With the ordinary thermometers the temperature 
may be observed at the surface and ordinarily not more than three inches 
l)elow the svu'face. 



28 



DEPARTMENT OF PUBLIC INSTRUCTION. 



To insert the bulb of an all-glass thermometer below the surface of the 
ground a hole must first be made with an iron or steel rod. If the surface 
is dry or loose it may be necessary to set a casing of paper or wood about the 
top of the hole to prevent the loose soil from falling into the hole to interfere 
with the inserting and removing of the thermometer. The hole should be 
so made that the center of the thermometer bulb shall stand at the depth at 
which the temperature is to be observed. After placing the thermometer 
in the soil it should be allowed to stand from 3 minutes to 5 minutes before 
reading in order that the mercury may come to rest. 

Experiment XVI. 

A Study of the Variations in Temperature of Natural Field or Garden Soils 
During the Day at Depths of o, 3, 6 and 12 inches respectively. 

Appanatus needed: 

1 carefully graduated ordinary thermometer. 
3 soil thermometers, 3-inch, 6-inch and 12-inch, 

(See Exp. XVII as alternative.) 

1 steel rod for making holes for soil thermometers. 

The experiment: 

1. Select some convenient uncropped area in a field or garden. 

2. With the iron rod make three holes of proper depth respectively to 
receive the three soil thermometers, casing the tops with paper or 
wooden tubes. 

(These holes should be about four inches apart in an east and west line.) 

3. Place the soil thermometers each in its proper hole, and the ordinary 
thermometer so that its bulb shall lie flat upon the surface of the 
ground three inches south of the middle soil thermometer. 

4. After five minutes quickly read all the thermometers and record the 
readings. 

5. At intervals of two hours during the day repeat 3 and 4, taking the 
first reading as early as sunrise if possible, and the last just before sun- 
set. 

Use a table something like the following for recording data: 



Soil Temperature. 





Thermometers reading at 






Depth . 


5 
a. m. 


7 
a. m. 


9 
a. m. 


11 
a. m. 


1 

p. m. 


3 
p. m. 


5 
p. m. 


7 
p. m. 


Time of 

highest 

reading. 


Average 
reading. 


in. . . 






















3 in. . . 






















6 in. . . 






















12 in.. 













































STUDY IN SOILS. 29 

6. Record any conclusions the data obtained may in your opinion war- 
rant. 

It would be well to repeat this experiment upon a number of days to note 
the progression of change, and the effect of clouds, rain, variation of air 
temperature, etc., upon soil temperatures. 

Experiment XVII. 

(To be performed in place of the previous experiment if the laboratory does 
not possess soil thermometers.) 

Apparatus needed: 
2 carefully graduated ordinary all-glass thermometers. 
1 iron rod for making holes for the thermometer. 

The experiment: 

1. Select some convenient uncropped area in a field or garden. 

2. With the iron rod make a hole in the soil deep enough to allow the 
thermometer to be inserted three inches into the soil, provided that at 
that depth the 50° mark on the stem stands above the surface of the soil. 
Otherwise make the hole deep enough to receive the thermometer so 
that the 50° mark on the stem shall stand just above the surface of the 
soil. Insert the thermometer. 

3. Place the other thermometer so that its bulb shall lie flat on the surface 
of the ground three inches south of the other thermometer. 

4. After the thermometers have been in place 5 minutes read them and 
record the readings. 

5. Repeat 4 at intervals of two hours during the day, as directed in Ex- 
periment XVI. 

Use a table similar to that used in Experiment XVI for recording data. 

Mention any interesting points which in your opinion the experiment has 
shown. 

It would be well to repeat this experiment upon a number of days to note 
the progressive changes, the effects of clouds, rains, etc., upon soil temperature. 

Experiment XVIII. 

The Effect of Slope upon the Temperature of the Soil. 

Apparatus needed: 

The same as in Experiment XVI if soil thermometers are available; other- 
wise the same as in Experiment XVII. 

The experiment: 

1. Select two convenient areas, one on a south slope and one on a north 
slope. Be sure the two areas are alike or nearly so in texture and color 
of soil. 

2. Using one of the methods described above (Experiments XVI and 
XVII) take and record one set of temperature readings on the south 
slope. 

3. Move the apparatus to the area on the north slope, take and record a 
set of temperature rea,dings as on the south slope. 

Plan to set the thermometers so that the readings on the north slope may 



30 



DEPARTMENT OF PUBLIC INSTRUCTION. 



be taken just 10 minutes after the readings were taken on the south 

slope. 
4. Ijeave the thermometers in place on the north slope and just 10 minutes 

after the first readings on the north slope were taken, take and record 

another set of readings. 
.5. Remove apparatus to the south slope and take and record a set of 

i-eadings, taking the readings just 10 minutes after the second set of 

I'eadings on the north slope were taken, 
(i Average the two sets of readings taken on the south slope, i. e., average 

the two surface readings, then average the 3-inch readings, and so on. 
7. Average the two sets of readings taken on the north slope. 
T'se a table like the following: 

The Effect of Slope upon the Temperature of the Soil. 





South Slope. 


North Slope. 


Depth of 

tliermonieter 

bulb. 


Time. 


Average. 


Time. 




• ^ 


:00 


:8U 


:1U 


:20 


Average. 


U ill 














3 iu 














(') ill 














12 ill 


. 



























8. Record any conclusions that in your opinion the data obtained war- 
rant. 
0. Why time the readings as indicated? 



EXPRRTMENT XTX. 

The Effect of Color upon the Temperature of Soil (with air-dry soils and 

laboratory conditions). 

Appcuratus and materials needed: 
8 one-c|uart pudding or bean pans. 
Three pint-lots of the following kinds of soil; light colored loam, dark 

loam, light colored sandy, all air-dry and sifted. 
2 quarts of clay soil, air-dry and sifted. 
5 c^uarts of muck soil, air-dry and sifted. 

One-half pint pulverized chalk, slaked lime or plaster of Paris. 
1 carefully graduated all-glass thermometer reading to degrees, or better, 

to half degrees. 
7 feet of No. 12 galvanized iron wire, and a perforated No. 14 cork to 

make a frame to hold the thermometer. 



.STUDY IN SOILS. 



31 



The expcrttHcnt: 

1. a. Fill oue pan with the clay soil. 

b. Fill one pan witli the light colored loam. 

c. Fill one pan with the dark colored loam. 

d. Fill one pan with the light sandy soil. 

e. Fill one pan with the muck soil. 

1". Fill one pan with the clay, leaving room foi- just enough muck to coni- 

])letely cover the surface of the clay, 
g. Fill one pan with the muck soil, leaving room for just enough of the 

fine clay to completely cover the surface, 
h. Fill one pan with the muck soil, leaving just room enough to com- 

l)letel_v cover the surface with plaster of Paiis, powdered chalk or 

slaked lime. 




Tig. 12. Showiuj; the pans of soil as they apiiear in Expciimcnt XIX. 




2. Set all of these i)ans with their contents out in the sunshine. (It will 
be better if the pans can be set down into the ground so that their rims 
stand just even with the surface of the ground. The rims of the 
pans should be but a few inches apart.) 

o. At any time l^etween 11 a. m. and 2 p. m. take the temperature of 
these soils one inch below the surface and record. 

jloTE — It will not be necessary to make a hole for the tliermometers in tliete soils. Carefully 
pii.sli the bulb of the thermometer to the proper depth. An open frame or gauge like that shown in 
Fig. 12 will prove helpful. 

4. In order that the results may be more reliable it will be better to take 
the thermometer reatlings just 5 minutes apart, taking two readings 
from each pan. Take the readings in the following order: 1, 2, 3, 4, 
5, 6, 7, 8, 8, 7, 6, 5, 4, 3, 2, 1. 

Place your readings in a table like this; 



32 



DEPARTMENT OF PUBLIC IN8T11UCTION. 
Effect of Color on Soil Temperatures. 





Pan 
1. 


Pan 
2. 


Pan 
3. 


Pan 
4. 


Pan 
5. 


Pan 
G. 


Pan 

7. 


Pan 

8. 




6 


g 

CD 

H 


6 


d, 


6 
a 


d 
fi 

^ 


a; 




i 


S 


a3 




jj 

H 


a, 

3 

^0) 


6 
3 
H 


a. 
3 


■ '- ' 


































Second readingH 
















^ 
































































































••- 











5. Average the first and second readings of each pan, placing the average 
in the proper place and indicate order of temperatures, from highest to 
lowest. 

(>. Place all of the pans under cover and away from the sunshine, and 
after twenty-four hours, with the pans still in the shade, take the tem- 
])eratures as in 4, introducing the readings into a tabic like the one used 
for the readings of the previous day. 

7. Complete the table as in 5. 

8. Record any conclusions suggested by this experiment. 

Experiment XX. 

Effect of Color upon Soil Temperature (with moist soils and field conditions). 

Apparatus and materials needed: 

A spade. 

22 linear feet of -^-in. x 6-in. boards. 
8 carefully graduated all-glass thermometers. 
1 iron rod to make holes for the thermometers. 

^ bu. each of the following soils: a clay, a light loam, a dark loam, a 
sandy, and a muck. 

The experiment: 

1. From a level area 2 ft. x 4 ft. remove the soil to the uniform depth 
of 7 inches. 

2. Cover the bottom of the excavation so formed to the depth of one inch, 
when well packed, with coarse sand. 

3. With the ^-in. x 6-in. boards divide this area into squares of about 
one foot on each side and six inches deep. 

4. Fill these squares as follows: 

a. With a clay soil, finely crumbled. 

b. With a light colored loam, finely crumbled. 

c. With a dark colored loam, finely crumbled. 

d. With a fine sandy soil, finely crumbled. 

e. With a muck soil, finely crumbled. 

f. With a clay soil, finely crumbled, leaving room for just enough muck 
soil to completely cover the surface of the clay. 



STUDY IN .SOILS. 



33 



g. AVith finely criiniblod muck soil, leaving room for just enough of 

the finely crumbled clay soil to completely cover the surface of the 

muck, 
h. With finely crumbled muck soil, leaving room for just enough plastei" 

of Paris, ground chalk or slaked lime to completely cover the stu'face 

of the muck. 

5. With a garden sprinkler and water thoroughly wet down the soils in 
all of these divisions. A goorl rain would do tlie work l)ettcr. 

6. Allow to stand twenty-four hours. 

7. On the first sunshiny day set one of the eight thermometers to the 
depth of two inches in the center of each of the eight areas, using the 
iron rod if necessary to make holes for the bulbs of the thermometers. 
Make and record readings at 10 a. m., 12 m., and 2 p. m. 

S. On the first cloudy day set the thermometers as indicated in 7 and 

make and record readings at 10 a. m., 12 m., and 2 p. m. 
Use a table like this: 



Effect 


of Color on Soil Temperature. 










♦ 


Suiisliiiiy (lay. 


t'luudy (by. 




10 
a. m. 


12 
m. 


2 
p. m. 


Av. 


Order. 


10 
a. m. 


12 

ni. 


2 
p. m. 


Av. 


Order. 


1 Clav 





















































































5 Muck 










































































1 


















1 1 








1 



Do the results suggest any methods for practice on the farm? 



Experiment XXI. 

The Effect of Moisture upon the Temperature of the Soil. 

Apparatus and 7naterials needed: 

2 one-quart pudding or bean pans. 

3 quarts finely crumbled, air-dry, sandy soil. 
1 carefully graduated all-glass thermometer. 

The experiment: 

1. Fill the two' pans with the soil in the manner described in Experiment 
XIX. 

2. Thoroughly moisten the soil in one of the pans and allow both pans of 
soil to stand together in the laboratory, but away from the sunshine, 
for a few hours. 

LOFC. 



34 



DEPARTMENT OF PUBLIC INSTRUCTION. 



3. Deteriuinc and record the temperuture of the soil in the two i)ans. . 

4. Now place the pans in the Huushine, and after two hours determine 
and record leniperatiu'e. 

Use a table like the following: 



Soil Temperatures as Influenced by Light and Moisture. 



In 

shade. 



Dry soil. 
Wet .soil. 



In 
suiishiiic. 



Difference. 



5. How wet shonld a field soil be? 

Why so wet? ^ 

Why not wetter? 
It might be well to repeat this experiment, nsing other soils. 

Experiment XXII. 

Effect of Tilth upon the Temperature of the Soil. 

Appardtiis needed: 
A spade. 

2 all-glass thermometers, accurately graduated. 
An iron rod to make holes for the thermometers. 

The expcriinent: 

1. Select a bare level iield or garden area 1 loot by 2 feet — one that has 
not recently been plowed or spaded. 

2. Thoroughly spade one-half of this area to the dejith of six inches. If 
the soil does not crundjle freel^y, it should be removed, placed in a pile, 
and thoroughly crundjled with the hands if necessary, and then returned 
to its place. 

Leave the other half ims{)aded. 

3. With the iron rod make a hole in the center of each half of the area, 
sufficiently deep to receive its thermometer to the depth of two inches. 

4. At one o'clock on the first clear day place the thermometers one in each 
of these holes and after 5 minutes read and record temperatures. 

5. At one o'clock on the first cloudy day place the thermometers one in 
each hole and after 5 minutes read and record the temperatures. 

Use a table like this; 



STUDY IN SOILS. 35 

Soil Temperatures as Influenced by Light and Cultivation. 





Cloudy 
weather. 


Sunshiny 
weather. 


Uncultivated 




Cultivated 








Difference . . . . . 









It may be desirable to make several readings at the hours indicated. 
It might be interesting also to make readings at other hours. 

6. If you discover differences in temperatures account for them. 

7. Do the results suggest any methods of farm practice? 



Experiment XXIII. 

Effect of Smoothness of Surface upon Soil Temperature. 

Apparatus needed: 

A spade. 

A garden rake. 

2 carefully graduated all-glass thermometers. 

An iron rod to make holes for the thermometers. 

The experiment: 

1. Select a level field or garden area two feet by four feet, one that has not 
recently been plowed or spaded. 

2. Spade the whole area to a depth of six inches. 

3. With the rake level off one-half (2 ft. x 2 ft.) of the spaded area, and 
with the spade pat dowm the surface even and smooth so as to resemble 
the rolled surface of a field. 

4. The remaining area should not be smoothed. The more rough and 
lumpy it can be left the better. 

5. On the first sunshiny day carefully set the thermometers, one in the 
center of each of these areas, to the depth of two inches below the sur- 
face of the ground, and make and record readings at 8 a. m., 10 a. m., 
12 m., 2 p. m., and 4 p. m. 

Be careful on the rough area not to measure down from the top of the 
lumps, but from the top of the ground. 

6. On the first cloudy day set the thermometers as above and make antl 
record readings. 

Use a table like this: 



36 



DEPARTMENT OF PUBLIC INSTRUCTION. 
Effect of Smoothness of Surface upon Soil Temperature. 




7. Fill out the table. 

Shall we roll our fields? Give reason for your answer. 

8. Study and compare results obtained in this experiment. 

Do the results in the two experiments indicate conflicting farm practice. 

The question concerning the rolling of fields suggests a modification of 
the experiment with dry earth mulches. 

In the jars supplied with water from the bottom once each week determine 
the moisture content of the two-inch mulch. Then after a fresh watering 
press down a portion of this mulch against the tamped soil below. After 
several hours determine its moisture content again and compare with first 
result. 

Why is a fine harrow used after rolling? 



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